1. Field of the Invention
The present invention relates to an electronic circuit apparatus having a plurality of circuit boards (substrates) mounting a plurality of electronic parts thereon, and a motherboard joined to the circuit boards, and a method for assembling such an electronic circuit apparatus. More particularly, the present invention relates to an electronic circuit apparatus capable of efficiently dissipating heat generated by power devices, and requiring reduced work for assembling the same.
2. Related Art
In a conventional electronic circuit apparatus such as disclosed in JP-A-8-111575, semiconductor chips are mounted directly on a circuit board. Positioning pins attached to the circuit board are inserted in holes formed in a motherboard to connect the circuit board and the motherboard. The circuit board is made of a metal to dissipate heat generated by power devices.
If this apparatus has a plurality of circuit boards to achieve many functions, the motherboard needs an increased number of holes for receiving the positioning pins of the circuit boards. The holes reduce a space available for mounting electronic parts on the motherboard. Assembling the circuit boards with the motherboard requires increased man-hours. Furthermore, heat generated by the power devices on the circuit boards cannot be absorbed nor dissipated efficiently, because the circuit boards are provided individually with heat radiating fins (heat sinks).